Automatic stop motion for knitting machines and the like



Jan. 18, 1949. G. E. HENNING ET AL 2,459,426

AUTOMATIC STOP MOTION FOR KNITTING MACHINES AND THE LIKE 2 Sheets-Sheet1 Filed May 14, 1947 FIG. 8

INVENTORS GE. HENN/NG CE. LEW/S ATTORNEV Jan. 18, 1949.

Filed May 14, 1947 2 Sheets-Sheet 2 H g 5 20 z '20 FIG. 6

so I i l 0575mm 3:] w AMPL lF/ER F; 55 f 53 FIG. 5

INVENTORS GE. HE NN/(VG C. E LE WIS A TTORNEV Patented Jan. 18, 1949AUTOMATIC STOP MOTION FOR KNITTING MACHINES AND THE LIKE George E.Henning and Clay E. Lewis, Baltimore, Md, assignors to Western ElectricCompany, Incorporated, New York, N. Y., a corporation of New YorkApplication May 14, 1947, Serial No. 747,976

13 Claims. 1

This invention relates to automatic stop motions for knitting machinesand the like, and more particularly to a stop motion device operable bythe vibration of the strand on which a textile covering is being appliedby a knitting machine, or the like.

In general, knitting machines consist of a plurality of knitting needleswhich are simultaneously reciprocated and rotated so as to combine aplurality of textile threads into a tubular knitted web. This knittedweb is utilized in many ways, one of the more common being to apply itas a textile covering around a continuously advancing conductor. Some ofthe limiting factors in operating knitting machines are the breaking ofone or more of the threads being engaged by the needles, the breaking ofone or more of the needles or the occurrence of a dropped stitch duringa knitting operation. When any of these con ditions occurs, a defectivecovering is knitted on the conductor and it is desirable to stop theknitting machines upon the occurrence of the faulty knitting operationof the machine.

An object of the invention is to provide new and improved stop motionsfor automatically stopping knitting machines and the like upon theoccurrence of a faulty knitting operation.

Another object of the invention is to provide a stop motion devicearranged to promptly stop a knitting machine upon the occurrence of abroken thread, broken needle or the dropping of a stitch.

A further object of the invention is to provide a stop motion devicearranged to automatically stop a knitting machine, or the like, uponexcessive vibration of the filamentary core upon which the knittingoperation is being performed by the machine.

One apparatus embodying features of the invention comprises a potentialgenerating element arranged to be engaged by an advancing core uponwhich a knitted tubular covering is being applied so that when theconductor is caused to vibrate out of its normal path of travel due to afaulty knitting operation, a potential is generated thereby which isutilized to effect an immediate stoppage of the knitting machine.

Other objects and advantages of the present invention will be apparentfrom the followin detailed description of a specific embodiment thereof,when read in conjunction with the appended drawings, in which:

Fig. l is a fragmentary, sectional View of the knitting mechanism of aconventional knitting machine disclosing a stop motion device embodyingthis invention applied thereto;

Fig. 2 is an enlarged sectional view taken alone line 2-2 of Fig. 1;

Fig. 3 is an enlarged section taken along line 33 of Fig. 1 showing apotential generating element, which is engaged by a core being advancedthrough the knitting mechanism shown in Fig. 1;

Fig. 4 is a fragmentary, sectional View taken along line 44 of Fig. 1;

Fig. 5 is a schematic wiring diagram of the electrical apparatusarranged to utilize the potential generated by the generating elementsshown in Figs. 1 to 4, inclusive, to effect a stoppage of the knittingmachine, and

Fig. 6 is a vertical, sectional view of an alternate design of apotential generating element arranged to be actuated by excessivevibration of a core being advanced through a knitting mechanism such asis shown in Fig. 1.

Referring now to the drawings, reference numeral l0 designates aconventional gear box forming part of a knitting machine, which isarranged to rotate a hollow tubular shaft l I and a jack cylinder l2forming part of a conventional knitting mechanism indicated generally at[3. The knitting mechanism to which this invention is applied isdisclosed in detail in B. W. Lerch et al. Patent 2,236,183 and S. E.Brillhart Patent 2,239,378, and only as much of this mechanism isdisclosed and described hereinafter as is necessary for a fullunderstanding of the present invention.

A pair of Wobbler cams [4-14 are secured angularly on the shaft H sothat when the shaft II is rotated, they serve to reciprocate a pluralityof needle jacks I5-l5 slidably positioned in slots l6l6 provided in thejack cylinder 12. A sleeve I! is fitted around the jack cylinder l2 soas to provide a suitable bearing surface for the needle jacks l5-l5 asthey are reciprocated. Each of the needle jacks I5-15 serves toreciprocate a knitting needle 20 slidably mounted in a slot 2! providedin a needle cylinder 22 secured to the jack cylinder 12 so that theslots 2| and 16, respectively, are aligned vertically with respect toeach other.

The jack cylinder [2 and the shaft H are rotated in the same directionbut at different speeds so that each of the knitting needles 20-20 willbe reciprocated a predetermined number of times per revolution of theneedle cylinder and the jack cylinder. The ratio of the speed betweenthe jack cylinder [2 and the Wobbler cams |4i4 depends upon the totalnumber of knitting needles 20--20 embodied in the knitting mechanism l3,and the number of threads being employed in the knitting operation. Oneof the more common knitting operations requires a knitting mechanismhaving fourteen knitting needles ZIP-29 equally spaced around the needlecylinder 22 (Fig. 2) operating upon six textile threads, such as threads2323 (Fig. 1).

In a normal knitting operation, it is customary for each needle toengage each thread once during each complete revolution of the knittingneedle. If the above-mentioned arrangement of needles and threads wereemployed, each needle must make six complete reciprocations perrevolution of the jack cylinder and needle cylinder. In the operation ofthe knitting mechanism 33, the textile threads 2323 are drawn fromsuitable supply cops (not shown) and pass through their respectiveguides like the guide 24 mounted on a thread guide spider 25 adjustablymounted on a support 26 forming part of the knitting machine. Each ofthe threads 23-23, after passing through its respective guide 24, ispassed around a guide 21 positioned adjustably on the support 26immediately above and concentric with the knitting needles --20. In thismanner, the threads 2-3-23 are fed to the knitting needles 2Il2ll from aplurality of equally spaced points about a circle in a symmetricalpattern and, upon rotation of the Wobbler cams E i-44 and the jackcylinder H, the needles engage the threads 23-23 and form a conical,tubular web 30.

A filamentary core 3 I, such as an insulated conductor, is advancedthrough a central aperture provided in the needle cylinder 22, the jackcylinder [-2 and the shaft l I at a constant rate of speed by a suitablecapstan (not shown). The knitting mechanism l3 serves to apply thetubular web 39 tightly around the advancing core to form a textilecovering 32 thereon. A guide 33 is secured on the support 255 for thepurpose of maintaining the path of travel of the core 3i substantiallycentral with respect to the knitting needles 2B2ll. Due to the fact thatthe needles 20-20 are equally spaced around the needle cylinder 22 andthe threads 2323 are fed to the knitting needles in a symmetricalpattern, the core 3| will travel in a substantially centralized paththrough the knitting mechanism :6 3. Such an arrangement of the knittingneedles 20-20 and the threads 2323 produces, under a normal operation ofthe mechanism IS, an equal tension at all points around the web 30,thereby causing the core to pass through the knitting mechanism withoutoscillating in any .direction, except for the normal vibration inherentin the knitting machine.

However, in the event of a broken thread, a broken needle or a droppedstitch, the symmetrical pattern of the knitting operation being per--formed by the knitting mechanism i3 becomes unbalanced, resulting in anunequal pull at some point around the web 30. When such an unbalancedknitting condition occurs around the web 30, the Web and the core onwhich it is being formed are caused to oscillate at a relatively highfrequency transversely to the vertical axis of the core and principallyalong an axis joining the strong side and Weak side of the web 30. Dueto the peculiar construction of the knitting mechanism I3, thisoscillation of the Web 30 and the core 3| may be in any one of aplurality of directions with respect to the rotary knitting operation ofthe knitting mechanism l3.

For example, should one of the threads 2323 break, the knittingoperation performed therewith terminates and the web 30 collapses assoon as all the needles associated therewith pass the broken thread.During the period in which the web 3!! is collapsing because of thebroken thread, the knitting operation becomes highly unbalanced, butthis unbalanced condition remains fixed along one axis, with respect tothe web due to the fact that the threads are not rotating. Looking atFig. 2, this fixed aXis of oscillation may fall along the axis A-A, theaxis 13-13 or along an intermediate axis, depending upon which one ofthe threads 23-23 breaks. However, when a needle breaks or a droppedstitch occurs, the unbalanced knitting operation does not remain fixedwith respect to the web but travels around the web with the needles,whereupon the core oscillates successively along many axes around theweb.

When faulty knitting operations occur, a defective covering is formed onthe advancing core. Hence, it is desirable to effect a quick stoppage onthe knitting machine before too great a length of the core contains adefective covering. The oscillating movement of the web 30 and the core3| 0n the occurrence of a faulty knitting operation is utilized inaccordance with the present invention to arrest the movement of theknittingmachine and the core automatically.

An eye 35 (Figs. 1 and 4-) is formed on the end of a detector rod 36 sothat it completely encircles the core 3! being advanced through theknitting mechanism E3. The detector rod 36 is secured in a conventionalpotential generating crystal cartridge 37 by means of a thumb screw 38.While the crystal cartridge 31 may be of any well known design, one typeparticularly suitable for this purpose is the lever type cartridge ModelW-56A, manufactured by Shore Brothers, Incorporated, of Chicago,Illinois, .and having a peak output voltage of 4.3 volts.

The crystal cartridge 37 is mounted on a plate M which is hingedlymounted on a support M by means of a pin 52. The support 4! is in turnpivotally mounted on the spider 25 by means of a pin $3. The pivot pointof the support 4| on the spider '25 is arranged with respect to thecentral axis of the cartridge 37 so as to cause the cartridge 31 and thedetector 36 secured therein to swing inwardly against the core 31 and tocreate a static pressure against the crystal element of the cartridge 3Tcommensurate with the operating characteristics of the cartridge. Thisarrangement provides for pivotal movement of the cartridge 31 in twodirections, whereupon maximum actuation of the crystal element of thecartridge 31 and maximum potential output are obtained by theoscillations of the core 31 along the axis BB, while oscillations of thecore along the axis A-A merely pivot the entire cartridge about the pin42.

Due to the inherent characteristic of the type of crystal potentialgenerating element selected, the cartridge 31 is directional along theaxis BB and only the oscillations of the core along this axis wouldprovide full actuation of the crystal element to produce the ratedoutput potential. Therefore, a second crystal cartridge 44 is mount edso as to be responsive to the oscillations of the core 3! along the axisA-A (Fig. 4). The cartridge 44 is identical with cartridge 31 and ismounted on a plate Q5 which is hingedly mounted on a support 46. Thesupport 46 is mounted pivotally on the spider 25 in substantially thesame manner as described for the plate '48 supporting the cartridge 31.

A detector rod M is secured to the cartridge i l in the manner describedfor securing the detector rod '35 to the cartridge 3?. The detector rodll has an eye 48 (Fig. 1) provided on the end thereof through which thecore passes befor entering the knitting mechanism 13. The crystalelement of the cartridge 44 is also directional and therefore is fullyactuated to provide maxi-- mum potential output only when the core 3| isoscillating along the axis A--A, while oscillation of the core along theaxis BB merely pivots the cartridge 44 about its pivot point on thesupport 46. However, when the core 3| oscillates alon an axisintermediate the axes A-A and B--B, the resultant oscillation along theaxes A-A and BB will actuate each crystal element a given amount, which,while somewhat less than full actuation will produce a combinedpotential suincient for the purpose of the invention.

Each of the cartridges 31 and 44 is provided with a pair of terminals towhich a suitable length of low capacity, rubber covered, shielded cable59 (Fig. 5) may be connected. Each of the cables 50 is connected to aconventional, single stage amplifier-detector unit 51 having anoperating coil 52 of a relay 53 connected in the output circuit thereof.The relay 53 is a sensitive D. (Z. relay commonly used in electronictube circuits and is provided with a normally closed contact 54 arrangedto be locked in the open position by a manually operable, reset lever 55when the coil 52 is energized. The contact 54 is connected in serieswith a manually operable snap switch 55, the contact 54 and the switch55 serv-- ing to control the continuity of a control circuit arranged tosupply potential to an operating coil 5? of a main line contactor 65!.The contactor 5i] is provided with normally open contacts Si- Si, whichupon energization of the coil 51 serve to connect a motor, indicatedgenerally at 52 and used to drive the gear box iii of the knitting Ina--chine, to a source of potential 63. The necessary operatin potential ofthe detector amplifier unit 51 is also supplied from the power source63.

When the knitting mechanism I3 is operating properly, the web 30 beingformed thereby and applied around the core 3| advancing through knittingmechanism will be substantially free of vibration, and the core willtravel in a substantially centralized path through the knittingmechanism. In addition, a perfect covering 32 is formed on the core 3|and substantially no lateral vibration or oscillation of the core isdiscernible. nor the crystal cartridge 44 is actuated to the extentnecessary to produce an output potential sufiicient to cause stoppage ofthe machine.

However, when one or more of the threads 3 23 or needles 2il20 break, orwhen a dropped stitch occurs in the formation of the web 39 due to thebreakage of a needle or other cause, a nonsymmetrical knitting operationoccurs which results in an unbalanced pull on the web 30. Thisunbalanced pull on the Web causes the Web to oscillate transversely ofthe central axis of the knitting mechanism 13. Since the advancing coreon which the Web is being applied is supported at spaced points aboveand below the point of formation of the web by the knitting needles, thecore 3| may be oscillated relatively easily. Therefore, this unbalancedknitting operation causes the core 3| to move laterally with respect toits vertical path of travel, which lateral movement automatically occursalong the axis joining the strong side and weak side of the web 30.

Assuming that the unbalanced knitting operation causes the core 3| tooscillate primarily along the axis 3-3, the crystal element of theHence, neither the crystal cartridge 31 cartridge 31 is undergoingmaximum displace ment and enerates its maximum output potential, whilethe cartridge 44 is merely swung about its pivot point. The outputpotential of the cartridge 31 is amplified by the amplifier detectorunit 5! and is applied directly across the terminals 0f the coil 52 ofthe sensitive relay 53 thereby energizing the coil. Upon energization ofthe coil 52, the normally closed contact 54 of the relay is opened andbecomes engaged by the manual reset arm 55. The opening of the contact54 deenergizes the coil 51 of the contactor 6D and the contacts Iii-6|dis-connect the motor 62 driving the knitting mechanism from the sourceof power 63, whereupon the operation of the knitting machine isterminated.

Likewise, if the oscillations of the core 3! are primarily along theaxis A-A, the crystal element of the cartridge 44 is undergoing maximumdisplacement and generates it maximum potential, which is applied acrossthe input terminals of the amplifier-detector uni-t 51. The potentialoutput of the cartridge 44 is amplified by the unit 5! and thereafteroperates the relay 53 to disconnect the motor 52 from its source ofpotential in the same manner as that described when the car tridge 37 isactuated by the oscillating core.

However, the primary oscillations of the core 5i may occur along someaxis intermediate the A-A. and 3-3. When such an oscillation of the core3! occurs, it is directed by means of the detector rods 36 and 41 to therespective crystal elements of the cartridges 3'! and 44. Each crystalelement, upon being displaced a predetermined number of times per secondby the oscillating core 31, generates a given voltage. Since neither ofthe crystal elements of the cartridges 3! and 44 is undergoing maximumdisplacement by such oscillation of the core, the voltage generatedthereby is somewhat less than the maximum value of the elements.Nevertheless, since both of the cartridges are connected to theamplifierdetector unit 5|, the combined potentials of the cartridges 3'!and 44 will be suihcient, when. amplified by the unit 5!, to operate therelay 53 and stop the knitting machine in the above-described manner.

From the foregoing description, it will be evident that the knittingmachine will be stopped automatically when the core 3| being advancedthrough the knitting mechanism i3 is oscillated in any direction by afaulty knitting operation resulting from a broken thread, a droppedstitch or a broken needle.

While in the above-described embodiment of the invention two crystalcartridges are employed to convert the mechanical vibrations of the coreinto electrical potential, it is obvious that three, four or morecartridges and associated detector rods may be disposed equidistantlyaround the core 3|, is desired. The selection of the size and number ofcrystal cartridges to be used in a particular application depends uponthe type of insulating operation being performed on the core, and theamplitude of the vibration upon the occurrence of a faulty insulatingoperation. There fore, such modifications and changes may be madewithout departing from the spirit and scope of the invention.

Fig. 6 discloses another type of crystal pickup element arranged to beactuated by the oscillations of the advancing core 3! upon the occur--rence of the faulty knitting operation. In this arrangement, a tube 10is secured at one end thereof in the core guide 33 fastened to thesupport v2E3 forming partof the knitting machine. The tube It] isprovided with an annular groove II which serves to form an inner ring l2within the tube, which ring has an inside diameter somewhat smaller thanthe inside diameter of the tube, but somewhat larger than'the outsidediameter of'the core ti being advanced therethrough. In the normaloperation of the knitting mechanism IS, the core 3!! will not contactthe ring l2 as it is advanced through the tube It.

A contact-type crystal microphone 73 is secured to the tube It so thatmounting shoes lid-l4 thereof engage the surface of the tube. Themicrophone 13 may be secured to the tube in any suitable manner, such asby a spring type clamp, by taping it to the tube or by applying asuitable cement between the mounting shoes -74 and the surface of thetube. For the purpose of the present invention, the microphone 73 willbe considered as being cemented to the tube Ill at the point where theshoes 'M'l4 contact the surface of the tube Ill. The crystal generatingelement provided in the microphone '13 is connected to a suitable lengthof shielded low capacity cable '55. While various contact-type ofmicrophones may be used in this manner, a particularly suitable type isknown commercially as the Vibromike, (Model VM-l), manufactured by theBrush Development Company, of Cleveland, Ohio. This particularmicrophone has anoutput voltage of one volt per one thousandth of aninch displacement of the crystal at 500 CPS.

In the operation of the latter stop motion device, when a core 35 beingadvanced through the knitting mechanism l3 is set to oscillate in aparticular direction due to the occurrence of an unbalanced knittingoperation, the core 3i in oscillating strikes the ring 72 of the tube 19.and sets up a vibration in the tube. This vibration is in turn pickedup by the mounting shoes M'M of the microphone l3 and displaces thecrystal element engaged by the mounting shoes so as to produce an outputvoltage across the terminals of the microphone. This output voltage ofthe microphone i3 is directed to an amplifier unit, such as theamplifier-detector unit 53 employed in'conjunction with the crystalcartridges 3'! and id described above. Thus, the output potential of themicrophone is amplified by the unit 5! sufiiciently to operate thesensitive D. C. relay 53 connected thereto, which in turn deenergizesthe main contactor 5B and causes the knitting machine motor 62 to bedisconnected from its source or" power, whereupon the knitting operationperformed by the knit ting machine is terminated.

Since the contact-type microphone i3 -is responsive to the mechanicalvibrations set up in the tube it by the abnormal oscillation of the corein any direction, only one microphone is needed regardless of thedirection of oscillation of the core with respect to the position of themicrophone F3 or the tube 10. As long as the tube is caused to vibrateand the mechanical vibrations are suflicient to produce sufficientdisplacement of the crystal generating element of the microphone, itsoutput voltage will be of a magnitude capable of being amplified andused to operate a sensitive relay to deenergize the motor driving theknitting machine.

While the above-described embodiments of the invention are directed tothe use of a crystal type of potential generating element .forconverting the oscillations of the core into electrical energy, .it isto be understood that a permanent magnet, moving coil type of potentialgenerating element may readily be'used to convert the oscillations of:the core into suitable electrical energy which may be utilized in theabove-described manner to terminate the operation of a knitting machine.

Although the above-described embodiments of the invention areparticularly well adapted as stop motion devices for a knitting machineof :the class described, they may be readily modified for use as stopmotion devices for braiding, Weaving, stranding, twisting and likemachines without departing from the spirit and the scope of theinvention as defined in the annexed claims.

What is claimed is:

1. In a knitting machine arranged to knit a textile covering around acontinuously advancing core which oscillates excessively upon theoccurrence of a faulty knitting operation of the machine, a potentialgenerating element arranged to be actuated by the oscillatory movementof the core, and means electrically connected to said potentialgenerating element for effecting a stoppage of the knitting machine whena predetermined potential is generated by said element.

2. In a knitting machine arranged to combine a plurality of threads toform a tubular covering over a core being advanced therethrough whichoscillates excessively when a defective covering is being applied to thecore, a stop motion device which comprises a potential generatingelement, supporting means for urging the potential generating elementinto contact with the advancing core so that when the core oscillatesexcessively a potential is produced by said element, and means operableby the potential so produced for effecting a stoppage of the knittingmachine.

3. A stop motion device for knitting machines arranged to combine aplurality of strands to form a tubular covering around an advancing corewhich is caused to vibrate more than a normal amount when a faultyknitting operation occurs, which comprises means for converting abnormalvibrations of the core in any direction into a predetermined electricpotential, and mean-s actuated by the electric potential so produced foreffecting a stoppage of the knitting machine.

4. In a knitting machine arranged to knit a tubular covering around acontinuously advancing core and including a motor for driving it, a stop.motion device which comprises a plurality of potential generatingelements arranged to be actuated only when the advancing core is causedto oscillate with-an amplitude in excess of a predetermined amount,means for amplifying the potential generated by the oscillating core,and means controlled by the amplified potential for deenergizing themotor driving the knitting machine.

5. In a knitting machine arranged to combine a plurality of textilethreads to form a tubular covering over a continuously advancing corewhose amplitude Of vibration is substantially increased above its normalamplitude of vibration .upon the occurrence of an unbalanced knittingoperation, a stop motion device which comprises apotential generatingelement arranged to be actuated only by vibratory motions of theadvancing core, means for amplifying the potential generated by saidgenerating element when the amplitude of vibration of the core exceeds"the amplitude of its normal vibration, and means operable by theamplified potential for terminating the operation of the knittingmachine.

6. A stop motion device for knitting machines arranged to combine aplurality of threads to form a tubular covering on a conductor beingcontinuously advanced therethrough, which comprises a pair of crystaltype potential generating elements arranged to be actuated when theadvancing core is caused to oscillate more than a predetermined amountin any direction by the occurrance of a faulty knitting operation, meansfor amplifying the resultant potential generated by the crystal elementswhen the core is oscillated, and means responsive to the amplifiedpotential for terminating the knitting operation.

7. A stop motion device for knitting machines arranged to combine aplurality of threads to form a tubular covering around a core beingcontinuously advanced therethrough which core oscillates excessivelywhen a faulty knitting operation occurs, which comprises a pair ofcrystal type potential generatin elements, an actuating rod secured toeach potential generating element and adapted to engage the advancingcore and transfer the oscillations of the core to their respectivecrystal generating elements, said crystal potential generating elementsbeing positioned so that their directional operating axes are disposedsubstantially 90 with respect to each other whereby they are responsiveeither singly or collectively to the oscillations of the core in anydirection, means electrically connected to the potential generatingelements for amplifying the resultant potential generated therein byexcessive oscillation of the core in any direction, and means operableupon the generation of such a potential to effect a termination of theknitting operation.

8. A stop motion device for knitting machines adapted to combine apluralityof threads to form a tubular covering on a core beingcontinuously advanced therethrough, which comprises a pickup cartridgehaving terminals and a crystal arranged to produce a predeterminedpotential across said terminals upon being actuated at high frequency,means for pivotally supporting the crystal cartridge adjacent to theadvancing core, an actuator secured in the cartridge and having an eyein the end thereof for engaging the advancing core at a point adjacentto the point at which the tubular covering is formed thereon by theknitting machine, said actuator serving to transmit oscillations of thecore to the crystal of said crystal cartridge and produce a givenpotential across the terminals thereof, an amplifier electricallyconnected to the crystal cartridge to amplify the potential generated bythe crystal when the core is oscillating due to a faulty knittingoperation, and a sensitive relay connected to the amplifier and arrangedto be actuated by the amplified potential for effecting a stoppage ofthe knitting operation when the core oscillates.

9. A stop motion device for knitting machines arranged to combine aplurality of threads to form a tubular covering around an advancing corewhich oscillates transversely to its path of travel when a faultyknitting operation occurs, which device comprises an elongated tubulardetector rigidly supported at one end so that the core may passtherethrough, said detector having a short bore formed therein of suchsize that it is engaged by the core when the core oscillates in anydirection due to a faulty knitting operation thereby causing the tubulardetector to vibrate, means secured to the tubular detector forconverting the mechanical vibrations set up 10 therein by theoscillating core into an electric potential, and means operable by sucha potential for eifecting a stoppage of the knitting operation.

10. In a knitting machine arranged to knit a textile covering around acontinuously advancing core which oscillates excessively upon theoccurrence of a faulty knitting operation of the machine, a potentialgenerating element, means engaged by the advancing core for imparting tothe potential generating element excessive oscillatory movements of thecore in any direction to cause a potential to be generated by saidelement and means associated with the potential generating element foreffecting stoppage of the knitting machine when a predeterminedpotential is generated by said element.

11. In a knitting machine arranged to combine a plurality of threads toform a tubular covering over a core advancing therethrough whichoscillates excessively when a defective covering is being applied to thecore, a stop motion device which comprises a potential generatingelement, means engaged by the advancing core for imparting excessiveoscillatory movement of the core in any direction to the potentialgenerating element so that when the core oscillates excessively apotential is produced by said element, and means operable by theresulting potential for eiiecting stoppage of the knitting machine.

12. A stop motion device for knitting machines arranged to combine aplurality of strands to form a tubular covering surrounding an advancingcore which is caused to vibrate more than a normal amount when a faultyknitting operation occurs, which comprises a potential generatingelement, means engaged by the advancing core for imparting vibrations ofthe core in any direction to the potential generating element wherebywhen the advancing core vibrates more than a normal amount a potentialis generated by said element, means for amplifying the potentialgenerated by the potential generating element, and means responsive tothe resulting amplified potential for effecting stoppage of the knittingmachine.

13. A stop motion device for knitting machines arranged to combine aplurality of threads to form a tubular covering around an advancing corewhich oscillates transversely to its path of travel When a faultyknitting operation occurs, which comprises an elongated tubular memberrigidly supported at one end so that the core may pass therethrough,said tubular member having a bore formed therein of such size that it isengaged by the core when the core oscillates in any direction due to afaulty knitting operation thereby causing the tubular member to vibrate,a crystal microphone secured to the tubular member for converting themechanical vibrations set-up therein by the oscillating core into anelectrical potential, and means operable by the resulting potential foreffecting stoppage of the knitting machine.

GEORGE E. HENNING. CLAY E. LEWIS.

REFERENCES CITED UNITED STATES PATENTS Name Date Scrantom Oct. 22, 1946Number

